Interest in identifying the most viable option for the treatment of biocontaminated ballast water has received worldwide recognition. It is estimated that approximately 3000 alien species are transported daily via ballast water making essential the need to deal with the aforementioned problem in the marine and coastal environments.
Allowing sea water ballast in certain compartments of the ship is the usual solution to compensate for lack of cargo loading in such a way that the operational characteristics of the ship are suitably adjusted. Accounting for movements of 7,000-10,000 species simultaneously and considering the vast amounts a typical commercial ship can carry, ballast water is the principal source of invasive species in coastal freshwater and marine ecosystems. Biological invasions are a leading cause of species extinctions and biotic homogenization worldwide. Ships' ballast water has been identified as an important vector for the introduction of non indigenous species, some of which may be responsible for significant negative commercial and health effects.
Problems associated with aquatic nuisance species have been estimated by the International Maritime Organization (IMO) to cost the global economy more than $100 billion annually, and have prompted the passage of the International Convention for the Control and Management of Ships' Ballast Water and Sediments in February 2004 that was modified by the 53rd Marine Environmental Protection Committee (MEPC 53) meeting in July 2005.
Many regulatory agencies and several state agencies have or are in the process of promulgating regulations governing methods of ballast water treatment (BWT) designed to eliminate the global transfer of alien species. Regulations have focused on two areas: approving specific technologies and discharge standards. The IMO published draft regulations including discharge standards that provide criteria for successful treatment. Discharge standards attempt to address both technical efficacy and enforcement practicality issues. However, it was clear from the published findings of MEPC 53 that technical difficulties remain in meeting these standards and the scope and detail of compliance monitoring remains a subject of debate.
One of the first guidelines recommended by the IMO was reballasting at sea and currently provides the best-available measure to reduce the risk of transfer of harmful aquatic organisms, but is subject to serious ship safety limits (due to instability issues). Even when it can be fully implemented, this technique is less than 100% effective in removing organisms from ballast water. Some parties even suggest that reballasting at sea may itself contribute to the wider dispersal of harmful species, and that island states located ‘down-stream’ of mid-ocean reballasting areas may be at particular risk from this practice.
According to IMO, the criteria for alternative ballast water treatment technologies are:                Safety for the ship and crew;        Environmental impact (it must not cause greater impacts than it solves);        Practicality (it must be compatible with ship design and operations);        Cost; and        Biological efficacy in terms of removing, killing or otherwise rendering inactive aquatic organisms and pathogens found in ballast water.        
Various alternative methods to reballasting have been developed, including:                Mechanical treatment methods such as filtration and physical separation;        Physical treatment methods such as sterilisation by ozone, ultra-violet light, or electric currents; electro-ionisation; gas super-saturation; and heat treatment;        Chemical treatment methods such adding oxidising or biocidal chemicals to kill organisms; and        Various combinations of the above.        
European Patent Application EP 1 717 205 A1 discloses removal of microbes to convert an untreated liquid to a clean harmless treated liquid, characterized in that the treatment of the liquid comprises a mechanical treatment for damaging microbes present in a liquid to effect extinction of the microbes and sterilization, combined with a chlorination in which a chlorine-containing substance is formed from a liquid and injected into a liquid to thereby effect microbe extinction and sterilization. There is further provided an electrolytic circulation system comprising applying a detoxification treatment for extinction of microbes in seawater and sterilization by means of detoxification facilities on land or on the sea to seawater introduced through a seawater introduction channel and accommodating the seawater having been thus treated in a ballast water tank. As a result, facility and operating costs can be reduced. Extinction of microbes of unlimited size and sterilization can be securely achieved without any strength drop on the side of treated liquid accommodation body. Further, the space for installation of detoxification apparatus for ballast water in ships can be reduced to thereby enable increasing of loading space for cargo, etc. Still further, on existing ships, the hull rework cost for installation of detoxification apparatus can be minimized.
US Patent Application No. US 2003 012 804 and PCT Patent Application No. WO 01/60971 disclose a method of controlling target aquatic microorganism pest populations by exposing the target population to an effective amount of an aquacidal compound. The aquacidal compounds are selected from the group consisting of quinones, anthraquinones, naphthalenediones, quinine, warfarin, coumarins, amphotalide, cyclohexadiene-1,4-dione, phenidione, pirdone, sodium rhodizonate, apirulosin and thymoquinone. The method is particularly effective for treating ballast water of ships or other enclosed volumes of water subject to transport between or among geographic areas to control the relocation of plants, toxic bacteria, and animals contained in the water.
US Patent Application No. US 2003 029 811 discloses systems and methods for effectively and economically annihilating non-indigenous marine species and pathogenic bacteria in ship ballast water. A preferred embodiment comprises adding a killing agent to ballast water tanks and subsequently adding a reducing agent to the container. Oxygen is subsequently introduced to the ballast water to eliminate any excess reducing agent, and to ensure compliance with the dissolved oxygen discharge requirements of the receiving water.
US Patent Application No. US 2003 129 645 discloses apparatuses and methods of a ballast water treatment system. The ballast water treatment system includes a control system and a ballast tank system. The control system controls the concentration of a biocide in the ballast tank system. In addition, the ballast water treatment system can be implemented in a vessel. The ballast water treatment system includes a control system, a biocide generation system, and a ballast tank system. The control system is capable of controlling the concentration of a biocide in the ballast tank system by controlling the amount of the biocide feed into the ballast tank system from the biocide generation system. Further, the ballast water treatment system involves methods for controlling organisms in ballast water of a vessel. A representative method includes providing the ballast water, and treating the ballast water with chlorine dioxide.
Another available chemical treatment for ballast water is the use of SeeKleen®. SeeKleen® is a commercial product marketed for use as natural biocide for ballast water treatment. Seakleen® is based on an antibiotic-medicinal, and more particularly menadione, also known as vitamin K3. Among the organisms claimed to be controlled are phytoplankton species, toxic dinoflagellates, dinoflagellates cysts, zebra mussel larvae, sheepshead minnow eggs and larvae, fathead minnow larvae, mysid shrimp larvae, grass shrimp larvae, copepods, spiny water flea, benthic amphipod protozoans and bacteria (E. coli and vibrio fisheri). However, experimental data show that while SeaKleen is very effective against zooplankton and other animal micro-organisms, it is thought to be less effective in killing plant organisms such as dinoflagellates or diatoms.
All the currently developed technologies have their limitations in application, in terms of efficacy, power consumption (operation cost), treatment flow rate, water turbidity and system corrosion, etc. More importantly, all the developed technologies have a limited treatment flow rate that is often less than the ballast and de-ballast rate of ship's normal operation that will delay the operation of ships. In addition, oxidation, de-oxygenation and ozone methods can cause corrosion problems to ship systems as well as posing a fire risk.
Therefore, there exists a need for a new technology that complies with IMO regulations, that is competitive in price, that is easy to install, operate onboard and maintain, that requires no major modification to the existing ballast systems, and that requires minimum training for crew to operate the system.
There also exists a need for an automated system and method for delivering, monitoring and controlling the dosing of the chemical formulation to ballast water.
Finally, there exists a need for a method of detecting viable micro-organisms in ballast water which is simple, reliable, fast, cost effective, and which does not require training of the operating crew or cumbersome equipment.
Treatment of water, and in particular sea water, is not only of interest in the field of ballast water. There exists other industrial applications in which the search for a composition capable of treating biocontaminated sea water has been the object of much research. One such application is the use of injection water for oil recovery.
During oil recovery from an oil well, the oil is initially driven to the surface by a number of natural mechanisms. This constitutes the primary recovery stage. These mechanisms include expansion of natural gas near the top of the reservoir, expansion of gas dissolved in the crude oil, gravity drainage within the reservoir and upward displacement of oil by natural water. However, the primary recovery stage typically provides a recovery factor of approximately 5-15% of the original oil.
When the underground pressure becomes insufficient to force the oil to the surface of the oil well, an increase in the recovery factor can be obtained by applying secondary recovery methods. These methods typically include gas injection and water injection. The use of secondary recovery techniques typically increases the recovery factor to approximately 15-40%.
A convenient source of fluid for injection is the produced water from the well. In an offshore environment, seawater is often the preferred source of injection water. Whichever source of water may be chosen, the purity of the water will affect the level of contaminants which are injected into the oil well. The presence of contaminants may cause ‘plugging’, i.e. the clogging of the well pores, which causes undesirable reduction of the recovery factor. The presence of contaminants may also cause scaling of the injection equipment. Additionally, the presence of bacteria such as sulphate reducing bacteria may cause ‘souring’ of the reservoir, i.e. contamination of the oil with hydrogen sulphide. Souring reduces the value of the produced hydrocarbons and requires expensive production equipment and materials to cope with the aggressive nature of the produced fluids.
Therefore, there exists a need for a composition capable of treating effectively injection water used in oil recovery.
It is an object of at least one embodiment of the present invention to seek to obviate or at least mitigate one or more disadvantages in the prior art.
It is an object of at least one embodiment of the present invention to provide a chemical composition capable of killing in situ aquatic invasive species in waters, typically sea water, and which is safe to be disposed of in the marine environment.
It is an object of at least one embodiment of at least one aspect of the present invention to provide an automated system for delivering, monitoring and controlling the dosing of the chemical composition to ballast water.
It is an object of at least one embodiment of at least one aspect of the present invention to provide a method of detecting micro-organisms in ballast water.